Is it OK to attach a CTEK or battery charger to the jump ports under the hood while changing the battery so I don't lose my settings and have to go through all the re-learning stuff (windows, steering angle, etc.)?

Is it OK to attach a CTEK or battery charger to the jump ports under the hood while changing the battery so I don't lose my settings and have to go through all the re-learning stuff (windows, steering angle, etc.)?

I think you'll only lose your time and date on radio. When I went for the airbag recall they disconnected the battery and I did not notice any settings gone.

I wonder if the dealer did that for me when I had mine in last year for the airbag recall...

Ya I'm not sure, I was watching the tech like a hawk and saw he went into the trunk to reconnect the battery after he was done with the airbag, and basically started the car and drove out into the parking.

Recently I changed my battery after 10 years with the original. I used a CTEK charger to keep it topped up. I would have gone longer with the original but only did it because the car was in for a recall and thought of saving myself another trip to the stealer in case!

I have a 2012 BMW M3 E92. 2012 Original battery, BUT purchased a CTEK Charger May 30, 2015. Today 10/23/2018 I decided to replace IT only due to it being 6 years old. Battery seems 100% thanks to CTEK but I feel it might go bad when I’m in the middle of no where so wtf. Will use CTEK Charger right away to maintain another OEM BATTERY starting on replacement date. 6 years in hot hot Florida is pretty good and I’m not interested in setting any records then having to pay big bucks to get rescued. I spend as much as new battery just getting food at Publix! Peace of mind, for late night, long road trips .......I have had batteries only last 4 years in Florida. Besides, I just punched a big hole in my rear tire in front of a Firestone. Tech lifted vehicle with out using lift points ie but lifted right next to lift
points. When I saw it incorrectly lifted, I terminated service. Super nice store manager gave me two PS2 for free for screw up as I was bummed out and felt I could not trust tech to continue. Left there and had a foreign car service center mount tires the correct way. My other choice was take them to court if there was damage? Inspection looked ok, I think most of the sub frame took the weight but still, wtf. Dealers are expensive but they do the work right most times. Just stay with your M3 if you are forced to go any other shops for work. Watch out. Goodyear tires lifted my G37 S on the front steering rods & grease joints! Cracked them! They wanted to do an alignment for the new tires on the M3 but I declined it, advised them I’d pay dealer for that service, tech had never done an M3. He Had worked on BMW’s before but not aware of jack points. Just Can’t take chance to save money these days unless you can observe the work being done, just my opinion of course. M3 could have been lifted via floor jack via the diff jack point just as easy I order to change two rear tires. Lol.

Just replaced my battery. I tried using one of these plugged into the OBD port to keep my settings alive while changing out the battery, but it didn't seem to work as it blew the OBD and dash fuse in the process. I replaced the 5A fuse and got it all working again, but ended up having to clear a bunch of fault codes and reset the time and re-initiate the window. Everything else seems fine and memory settings, etc. were retained.